Plasma display apparatus and its drive circuit

Abstract

In a plasma display apparatus and its drive circuit, a period that capacitance Cxa formed between an address electrode and an X-discharge maintaining electrode and capacitance Cya formed between the address electrode and a Y-discharge maintaining electrode are charged is provided when the address electrode is driven so that the address electrode is set to high-impedance state during a discharge maintaining period to reduce apparent capacitance. Furthermore, the charge period is set in a power withdrawing period and thereafter the address electrode is set to high-impedance state to change final arrival potential for power withdrawal to a discharge maintaining voltage.

1 . A plasma display apparatus including a display panel having first and second electrodes disposed alternately and a third electrode disposed opposite to the first and second electrodes, wherein
 a state that the third electrode is connected to fixed potential and a state that the third electrode is not connected to the fixed potential are provided as the state of the third electrode during one period that first and second discharge maintaining potentials having different values are applied to the first and second electrodes so that polarity of electric field between the first and second electrodes is changed alternately.   
     
     
         2 . A plasma display apparatus according to  claim 1 , wherein
 timing that the state of the third electrode is changed from the state that the third electrode is connected to the fixed potential to the state that the third electrode is not connected to the fixed potential is set after control for increasing potential at the first or second electrode from a state that the potential at the first or second electrode is lower potential of the first and second discharge maintaining potentials is started and before higher discharge maintaining potential of the first and second discharge maintaining potentials is applied to the first or second electrode.   
     
     
         3 . A plasma display apparatus according to  claim 2 , wherein
 timing that the state of the third electrode is changed from the state that the third electrode is not connected to the fixed potential to the state that the third electrode is connected to the fixed potential is set after potential at the first or second electrode falls from the state that the potential at the first or second electrode is higher potential of the first and second discharge maintaining potentials and before lower discharge maintaining potential of the first and second discharge maintaining potentials is applied to the first or second electrode.   
     
     
         4 . A plasma display apparatus according to  claim 3 , wherein
 the timing t 1  that the state of the third electrode is changed from the state that the third electrode is connected to the fixed potential to the state that the third electrode is not connected to the fixed potential, the timing t 2  that control for increasing the potential at the first or second electrode from the state that the potential at the first or second electrode is lower potential of the first and second discharge maintaining potentials is started, the timing t 3  that higher discharge maintaining potential of the first and second discharge maintaining potentials is applied to the first or second electrode, potential V(t 1 ) at the first or second electrode at the timing t 1 , higher potential Vs of the first and second discharge maintaining potentials and the power supply voltage Va of the drive circuit for driving the third electrode satisfy the following relation:
     Va> 2( Vs− V( t 1)) 
   and 
   t 1 ≠t 3 . 
   
     
     
         5 . A plasma display apparatus according to  claim 4 , wherein
 the timing t 1  that the state of the third electrode is changed from the state that the third electrode is not connected to the fixed potential to the state that the third electrode is connected to the fixed potential, the timing t 2  that the potential at the first or second electrode falls from the state that the potential at the first or second electrode is higher potential of the first and second discharge maintaining potentials and lower discharge maintaining potential of the first and second discharge maintaining potentials is applied to the first or second electrode, and the timing t 3  that control for increasing the potential at the first or second electrode from the state that the potential at the first or second electrode is lower potential of the first and second discharge maintaining potentials is started satisfy the following relation:
   t 2 ≦t 1 <t 3 . 
   
     
     
         6 . A drive circuit to drive a display panel including first and second electrodes disposed alternately and a third electrode disposed opposite to the first and second electrodes, wherein
 a state that the third electrode is connected to fixed potential and a state that the third electrode is not connected to the fixed potential are provided as the state of the third electrode during one period that first and second discharge maintaining potentials having different values are applied to the first and second electrodes so that polarity of electric field between the first and second electrodes is changed alternately.   
     
     
         7 . A drive circuit according to  claim 6 , wherein
 timing that the state of the third electrode is changed from the state that the third electrode is connected to the fixed potential to the state that the third electrode is not connected to the fixed potential is set after control for increasing potential at the first or second electrode from a state that the potential at the first or second electrode is lower potential of the first and second discharge maintaining potentials is started and before higher discharge maintaining potential of the first and second discharge maintaining potentials is applied to the first or second electrode.   
     
     
         8 . A drive circuit according to  claim 7 , wherein
 timing that the state of the third electrode is changed from the state that the third electrode is not connected to the fixed potential to the state that the third electrode is connected to the fixed potential is set after potential at the first or second electrode falls from the state that the potential at the first or second electrode is higher potential of the first and second discharge maintaining potentials and before lower discharge maintaining potential of the first and second discharge maintaining potentials is applied to the first or second electrode.   
     
     
         9 . A drive circuit according to  claim 8 , wherein
 the timing t 1  that the state of the third electrode is changed from the state that the third electrode is connected to the fixed potential to the state that the third electrode is not connected to the fixed potential, the timing t 2  that control for increasing the potential at the first or second electrode from the state that the potential at the first or second electrode is lower potential of the first and second discharge maintaining potentials is started, the timing t 3  that higher discharge maintaining potential of the first and second discharge maintaining potentials is applied to the first or second electrode, potential V(t 1 ) at the first or second electrode at the timing t 1 , higher potential Vs of the first and second discharge maintaining potentials and the power supply voltage Va of the drive circuit for driving the third electrode satisfy the following relation:
     Va> 2( Vs− V( t 1)) 
   and 
   t 1 ≠t 3 . 
   
     
     
         10 . A drive circuit according to  claim 9 , wherein the timing t 1  that the state of the third electrode is changed from the state that the third electrode is not connected to the fixed potential to the state that the third electrode is connected to the fixed potential, the timing t 2  that the potential at the first or second electrode falls from the state that the potential at the first or second electrode is higher potential of the first and second discharge maintaining potentials and lower discharge maintaining potential of the first and second discharge maintaining potentials is applied to the first or second electrode, and the timing t 3  that control for increasing the potential at the first or second electrode from the state that the potential at the first or second electrode is lower potential of the first and second discharge maintaining potentials is started satisfy the following relation:
   t 2 ≦t 1 <t 3 .   
     
     
         11 . A plasma display apparatus which reuses electric charge withdrawn from pixels to make the pixels emit light, wherein
 after the pixels are charged with the withdrawn electric charge at predetermined periods, the pixels are charged with new electric charge to be made to emit light and thereafter electric charge is withdrawn from the pixels, and   the pixels are set to non-high-impedance state during a period that the pixels are charged with the withdrawn electric charge,   the pixels being set to high-impedance state at least during the pixels are charged with the new electric charge.   
     
     
         12 . A plasma display apparatus according to  claim 11 , comprising
 a display panel including a plurality of pixels and   a drive circuit to charge the pixels with electric charge,   and wherein   the drive circuit charges the pixels with the withdrawn electric charge at predetermined periods and then charges the pixels with new electric charge to be made to emit light, so that electric charge is thereafter withdrawn from the pixels,   the drive circuit setting the pixels to non-high-impedance state during the period that the pixels are charged with the withdrawn electric charge,   the drive circuit setting the pixels to high-impedance state during the period that the pixels are charged with the new electric charge.   
     
     
         13 . A plasma display apparatus according to Claim  12 , wherein
 the pixels are set to high-impedance state from first predetermined timing within a period after the second half of the period that the pixels are charged with the withdrawn electric charge and before the pixels are charged with the new electric charge until second predetermined timing within a period after the second half of the period that electric charge is withdrawn from the pixels and before the pixels are recharged with the withdrawn electric charge.   
     
     
         14 . A plasma display apparatus according to  claim 13 , wherein
 the first timing is further defined after charging of the pixels with the withdrawn electric charge is ended and   the second timing is further defined after the pixels are reset to predetermined potential after electric charge is withdrawn from the pixels.   
     
     
         15 . A plasma display apparatus which reuses electric charge withdrawn from pixels to make the pixels emit light, comprising:
 a display panel including a first electrode arranged on one side of the display panel and a second electrode disposed on the other side of the display panel to form the pixels between the first and second electrodes;   a first drive circuit to drive the first electrode using a power supply circuit; and   a second drive circuit to drive the second electrode using the power supply circuit;   the first drive circuit applying voltage to the first electrode using the power supply circuit to make the pixels emit light after voltage is applied to the first electrode using the withdrawn electric charge at predetermined periods and thereafter withdrawing electric charge from the pixels through the first electrode;   the second drive circuit connecting the second electrode to a fixed potential end during period that the first drive circuit applies voltage to the first electrode using the withdrawn electric charge and separating the second electrode from the fixed potential end at least during period that the first drive circuit applies voltage to the first electrode using the power supply circuit.   
     
     
         16 . A plasma display apparatus according to  claim 15 , wherein
 the fixed potential end is ground.   
     
     
         17 . A plasma display apparatus according to  claim 15 , wherein
 the second drive circuit separates the second electrode from the fixed potential end from a first predetermined timing within a period after the second half of the period that the first drive circuit applies voltage to the first electrode using the withdrawn electric charge and before the first drive circuit applies voltage to the first electrode using the power supply circuit until a second predetermined timing within a period after the second half of the period that the first drive circuit withdraws electric charge from the pixels and before the first drive circuit applies voltage to the first electrode again using the withdrawn electric charge.   
     
     
         18 . A plasma display apparatus according to  claim 17 , wherein
 the first timing is further defined after application of voltage by the first drive circuit to the first electrode using the withdrawn electric charge is ended and   the second timing is further defined after the first drive circuit resets the pixels to predetermined potential after the first drive circuit withdraws electric charge from the pixels.   
     
     
         19 . A plasma display apparatus which reuses electric charge withdrawn from pixels to make the pixels emit light, comprising:
 a display panel including first and second electrodes arranged on one side of the display panel and a third electrode disposed on the other side of the display panel, the pixels being formed between the first and third electrodes or between the second and third electrodes;   a first drive circuit to drive the first electrode using a power supply circuit; and   a second drive circuit to drive the second electrode using the power supply circuit;   the first or second drive circuit applying voltage to the first or second electrode using the power supply circuit to make the pixels emit light after voltage is applied to the first or second electrode using the withdrawn electric charge at predetermined periods and thereafter withdrawing electric charge from the pixels through the first or second electrode;   parasitic capacitance formed between the first and third electrodes being connected in series to parasitic capacitance formed between the second and third electrodes at least during a period that the first or second drive circuit applies voltage to the first or second electrode using the power supply circuit.   
     
     
         20 . A plasma display apparatus according to  claim 19 , wherein
 the parasitic capacitance formed between the first and third electrodes is connected in series to the parasitic capacitance formed between the second and third electrodes from a first predetermined timing within a period after the second half of the period that the first or second drive circuit applies voltage to the first or second electrode using the withdrawn electric charge and before the first or second drive circuit applies voltage to the first or second electrode using the power supply circuit until a second predetermined timing within a period after the second half of the period that the first or second drive circuit withdraws electric charge from the pixels and before the first or second drive circuit applies voltage to the first or second electrode again using the withdrawn electric charge.